Preservation of electronic equipment during earthquakes and after shocks for the maintenance of communications and other purposes is a major concern of earthquake preparedness. As there is a critical need for communications immediately after an earthquake in a populated area, it is important for communications equipment to be able to withstand the most severe earthquakes or seismic shocks that can be expected to occur in the vicinity of such equipment.
With the introduction of electronic and fiber optic telephone switching equipment, the density of calls being handled in one equipment rack or network bay has advanced significantly. Today as many as 20,000 telephone lines could be interrupted with the loss of one bay of equipment. This has made the reliability of telephone switching equipment, communications equipment or other sensitive electronic equipment and its supporting structure critically important. Traditionally earthquake protection has been achieved by providing equipment racks or network bays with relatively massive bracing or using heavier materials, which both add significantly to the labor and cost in manufacturing. In prior configurations, design of equipment racks have utilized different gauge materials to provide desired structural integrity, but results in added cost and problems in assembly.
During seismic motion, the base of a tall, slender, frame moves with the floor to which it is anchored. If the frame is sufficiently rigid and well anchored it will closely follow the motions of the base and floor. If, however, the frame is more flexible, it will move at a rate different to that of the base and floor, and consequently experience high stresses and deflections. To accommodate desired operation in different seismic environments, the equipment rack must provide structural integrity to a desired level balanced with cost and other desired attributes of such an equipment rack. For example, it may be desirable to allow an equipment rack to be used to support various electronic or other equipment, but such equipment requires differing mounting requirements and space. Known equipment racks do not provide modularity or adaptable uses to accommodate differing equipment or environments.
U.S. Pat. No. 4,553,674, Casing Construction for Electronic Equipment, shows an equipment rack with a square wave type shape for the side rails. U.S. Pat. No. 4,899,892, Earthquake-Resistant Electronic Equipment Frame, describes a side rail having an inverted-V extending the length of the side rail to stiffen the side rail. U.S. Pat. No. 5,004,107, Earthquake Braced Racks, describes an electronic equipment that uses a reinforcing gusset, which includes a floor section that partially overlaps the floor of the base. U.S. Pat. No. 5,284,254, Rack for Electrical Equipment, describes an equipment rack that uses a two part removable cover attached to a base. U.S. Pat. No. 5,819,956, Rack for Electrical Equipment, discloses an equipment rack that reinforces the upper portion of the rails with a channel like bracket and reinforces the lower portion of the rails with an L shaped bracket. U.S. Pat. No. 5,979,672, Earthquake Resistant Enclosure for Electronic Equipment, describes an equipment rack where a top rail, bottom rail and side rails are formed using corrugated metal. U.S. Pat. No. 5,983,590, Earthquake Resistant Equipment Rack, shows an equipment rack that uses a base with integrally formed upright walls along with U-shaped gussets reinforcing a rail to top connection and corner gussets welded to the base. U.S. Pat. No. 6,006,925, Equipment Rack System, describes an equipment rack that uses side rails that have a two cycle reflected square wave shape to reinforce the side rails. U.S. Pat. No. 6,202,860, Electronic Equipment Enclosure, shows another equipment that uses corrugated metal for the top rail, bottom rail and side rails.
Therefore, in light of the foregoing deficiencies in the prior art, Applicant's invention is herein presented.